Mixing shield



FIG. 1 is a perspective view of a mixing shield showing my new design;

FIG. 2 is a front side elevational view thereof, all other side elevational views being identical thereto;

FIG. 3 is a top view thereof; and,

FIG. 4 is a bottom view thereof.

The broken line showing of a paint can is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a mixing shield, as shown and described. 